Filter segments or filter for cigarettes and method for the production thereof

ABSTRACT

A method for producing filter segments for one of multi-segment filters and filters for tobacco products. The method includes extruding a rod-shaped extrudate from a starting material, and wrapping the extrudate with at least one of a compressible and an elastic first material. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

[0001] The invention relates to a method for producing filter segments for multi-segment filters or filters of the tobacco processing industry, whereby an extrudate is initially produced from components of the filter segments or filters by means of an extrusion process. The invention further relates to a corresponding filter segment for a multi-segment filter or a corresponding filter of the tobacco processing industry.

[0002] A method for producing a filter rod is known, e.g., from U.S. Pat. No. 5,523,036. This document describes how a filter rod is first extruded by means of an extruder and subsequently wrapped with a wrapping paper strip. At the end of the process the filter rod is cut into filters of multiple unit lengths. According to U.S. Pat. No. 5,523,036 the extruded filter material is a plastic material that is extruded in an extrudate rod with a diameter which is greater than the exit orifice of the extruder.

[0003] A smoke filter for cigarettes and a method for its production are known from DE-OS 1 692 945. The smoke filter is a body that is produced by sintering thermoplastic and hydrophobic plastic foam that is pulverized into the smallest particle size, and has a cross section adapted to a cigarette. This filter body can be used by itself or in combination with a conventional, e.g., acetate filament filter or an identical type of filter body one behind the other or parallel to one another, in order to thus further improve or selectively influence the filter effect.

[0004] These filters or filter elements have the disadvantage that they are relatively susceptible to shocks and in general are very sensitive to mechanical strains so they can easily be damaged during further processing.

[0005] In contrast, the object of the invention is to disclose a method for producing filter elements or filters that makes it possible in a simple and cost-effective manner to produce filters and filter elements or filter segments for multi-segment filters which are relatively unsusceptible to mechanical strains. Another object of the invention is to disclose a filter or a filter segment for a multi-segment filter of the tobacco processing industry that itself is unsusceptible to mechanical stresses.

[0006] This object is attained through a method for producing filter segments for multi-segment filters or filters of the tobacco processing industry, whereby a rod-shaped extrudate is initially produced from a starting material by means of an extrusion process, which extrudate is further processed in that in a further process step the extrudate is wrapped with a compressible and/or elastic first material.

[0007] By providing the extrudate with a compressible and/or elastic first material, it becomes less susceptible to mechanical strains during further processing and during further transport. The method according to the invention thus renders possible a very simple and cost-effective way of developing filters or filter segments more capable of bearing mechanical stress.

[0008] The extrudate cut into corresponding lengths is a filter component and has a relatively low draft resistance and thus a low density. Due to the powdery components this is very unsusceptible to mechanical stresses if it is not wrapped according to the invention. The permeability to air corresponds to that of conventional filters or filter segments.

[0009] The extrudate is preferably heated before the process step of wrapping, through which the extrudate can be further hardened or also chemically altered. In a preferred exemplary embodiment the process step of heating takes place at a temperature range of 600° C. to 1000° C. With an extrudate that features e.g., activated carbon in granulate form and a binder such as, e.g., polyfurfuryl alcohol, the treatment step of heating at a temperature range of 600° C. to 1000° C. leads to the carbonization of the binder. This step can also be called a pyrolysis treatment.

[0010] Heating by means of microwaves is a particularly simple method of heating.

[0011] The first wrapping material is preferably completely impermeable to smoke or nearly impermeable to smoke in particular in the longitudinal axial direction. The filter properties of the extrudate and the draft resistance of the filter segment are thus not influenced or only slightly influenced due to the wrapping with the first material. In addition, providing a compressible and/or elastic first material has the advantage that fluctuations in the diameter of the extrudate can be compensated for so that a rod that is uniform in terms of diameter and thus filters or filter segments that are uniform in terms of diameter can be produced. In addition, this material can also be used to compensate for any differences in diameter of filter segments in a multi-segment filter, which is a very great advantage. During the transport of the filter segments of a multi-segment filter there is furthermore the advantage that holding the segments in flutes by suction air is improved, since the suction air is no longer applied to the air-permeable extrudate but to the wrapping that is only slightly permeable to air or impermeable to air.

[0012] Wrapping with the first material can take place through a further extrusion process, by dipping in a melting bath or by wrapping with strips of the first material and/or by wrapping with a first material arranged on an in particular soft carrier strip. These listed variants should be regarded as particularly effective and quick.

[0013] If preferably the first material is a hot melt adhesive, in particular an ethylene vinyl acetate copolymer, materials can be used that are already very well known in the production of filters of the tobacco processing industry. To this end the hot melt adhesive is preferably applied in a relatively thick layer. Preferably the first material is foamed, whereby in particular preferably a closed-pore foam is produced. By using a closed-pore foam as a first material in particular the desired impermeability to smoke or an almost complete impermeability to smoke is achieved. As an alternative, the first material can be a cellulose acetate tow of high density which itself preferably is also essentially impermeable to smoke. The cellulose acetate tow features a high density if it is, e.g., greatly rippled. In one embodiment of the invention, the cellulose acetate tow is wrapped around the extrudate transverse to the rod direction of the extrudate, in particular spirally. The preferred direction of the filaments in the cellulose acetate tow is then aligned transverse to the rod direction of the extrudate. The first wrapping material can also be an air-layed fibrous web that is produced according to a process that is described in EP 003 20 44 B 1.

[0014] Subsequently the extrudate that is wrapped with the first material is preferably wrapped with a second material so that as far as the outward appearance is concerned a per se customary filter segment or a per se customary filter can be achieved. A particularly simple realization of the wrapping of the extrudate is achieved when the extrudate is wrapped in a rod process with the first and/or the second material. To this end, e.g., the applicant's KDF 2E machine known among experts is suitable.

[0015] Finally, the wrapped extrudate is preferably cut into segments of predeterminable length.

[0016] The object is further attained through a filter or a filter segment for a multi-segment filter of the tobacco processing industry which is produced in particular according to the above-mentioned method and that is provided with a core that is in particular susceptible to shocks, that is wrapped with at least one first wrapping material that is compressible and/or elastic and in particular essentially impermeable to smoke or completely impermeable to smoke. The impermeability to smoke or the essentially present impermeability to smoke should hereby preferably predominate in the longitudinal axial direction, whereby longitudinal axial should be understood to mean the rod alignment of the extrudate or of the core. The core is preferably composed of an extrudate.

[0017] The invention is described below without restriction of the general inventive concept on the basis of exemplary embodiments, to which reference is expressly made regarding all inventive details not explained in further detail in the text. They show:

[0018]FIG. 1 A diagrammatic side view of a device according to the invention for producing filter segments for multi-segment filters or filters

[0019]FIG. 2 A sectional drawing of a corresponding filter segment or a corresponding filter, and

[0020]FIG. 3 Another exemplary embodiment of a device according to the invention for producing filter segments for multi-segment filters or filters of the tobacco processing industry.

[0021] In the following figures the same elements are labeled with the same reference numbers, so that a new introduction has been omitted respectively.

[0022]FIG. 1 shows in a diagrammatic view a device with which the method according to the invention can be carried out. An extrusion press 10, which can also be called an extruder, is provided in order to form an extrudate 11. Extrusion presses are known per se and are used in particular to produce corresponding, e.g., plastic molding masses in different shapes, such as plates, strips, pipes, hoses, casings, etc. Screw extrusion presses, also called extruders, are in particular suitable for this. To this end the molding mass is drawn from the supply container by the rotating screw of the extrusion press, conveyed, if necessary melted, and pressed out through a profiling nozzle. Regarding the process of extruding filter segments or filters, reference is made in particular to U.S. Pat. No. 5,523,036, in which this process is described. Reference is also made in particular to the other patents or patent applications cited in this patent which also provide the possibility of extrusion, such as in particular UK 451,683, UK 1,271,274, UK 1,341,400, UK 1,442,631, UK 1,456,908, UK 1,482,216, and U.S. Pat. No. 4,180,536.

[0023] As a starting material, e.g., activated carbon in granulate form can be provided which is mixed with a binder such as, e.g., polyfurfuryl alcohol. Zeolite grains (Al-Si oxide grains) mixed with water glass as a binder can also be used as starting materials. Other materials can also if necessary be added to achieve certain rod or extrudate properties. The corresponding materials are familiar to one skilled in the art from the prior art (see the above-referenced publications).

[0024] After the extrudate 11 has left the extrusion press 10, the extrudate is further processed in a processing device 14. As a processing device, e.g., an oven can be provided that, e.g., at a temperature range of 600° C. to 1000° C. converts the polyfurfuryl alcohol binder into carbon in the manner of a pyrolysis treatment. The processing device 14 can also be a microwave oven, which leads to the water glass hardening through the heat exposure.

[0025] The correspondingly processed rod of the extrudate 12 is conveyed further as a filter core rod 12 in the direction 25 of a rod-making machine 15 that can be, e.g., a KDF 2E of the applicant. On the way there a first wrapping material 18 is pulled off from a bobbin 17 and conveyed to the filter core rod 12 to wrap it. The first wrapping material 18 can hereby be, e.g., a hot melt adhesive such as ethylene vinyl acetate copolymer, which is applied to a thick, soft paper (tissue) as a thick adhesive layer, possibly also as a foam. In this case it is not necessary to provide another second wrapping material 21 that is pulled off from a bobbin 20. In this variant of the first wrapping material, the exemplary embodiment can thus be modified according to FIG. 1 such that the bobbin 20 and the second wrapping material 21 are omitted. In this exemplary embodiment the hot melt adhesive is applied so thickly that on the one hand the susceptibility to shocks of the then totally wrapped extrudate is reduced and also if necessary fluctuations in diameter can be compensated for.

[0026] As a variant, as first wrapping material a greatly rippled cellulose acetate tow can be used that is not mixed with a softener such as triacetin and that is wrapped around the rod transverse to the fiber direction. A wrapping can be carried out spirally such as, e.g., with cigarillo production machines.

[0027] After the first wrapping material 18 has been brought into the area of the extrudate 12, a second wrapping material 21, such as, e.g., a conventional paper strip, is pulled off from a bobbin 20 and also applied on the outside of the first wrapping material. After both the first wrapping material and the second wrapping material or only the first wrapping material in the exemplary embodiment with the hot melt adhesive that is applied to a thick, soft paper, is brought into contact with the extrudate 12, it is fed to a rod maker 15, e.g., of the type KDF 2E of the applicant. In this rod maker the first and/or second wrapping material is wound around the extrudate. Subsequently, the wrapped extrudate is cut into filters 16 by means of a knife device that is a component of each machine of type KDF. As a rule, these filters 16 are of multiple unit lengths and are then joined to cut tobacco rods in a filter tipping machine, e.g., a MAX 80E of the applicant, and processed to form filter cigarettes or they are divided into filter segments and processed with filter sections of the same or different type to form multi-segment filters.

[0028]FIG. 2 shows a cross section through a filter 16 according to the invention or a filter segment 24 according to the invention. The filter 16 or the filter segment 24 comprises a filter core 22, the first wrapping material 18 and the second wrapping material 21. The first and second wrapping material can also be provided with perforation holes in the course of further processing.

[0029]FIG. 3 shows another exemplary embodiment of a device by means of which a different process sequence is rendered possible.

[0030] As described above, an extrudate 11 is produced by means of an extrusion press 10, conveyed in the longitudinal axial direction 25 and processed in a processing device 14 to form a processed extrudate or filter core rod 12. The first wrapping material can now, e.g., by means of a melting bath 23 through which the filter core rod 12 is guided, be applied to this or wrapped around it. For example a hot melt adhesive that is located in the melting bath 23 is also suitable as the first wrapping material. A round nozzle 26 arranged behind it ensures that the hot melt adhesive and thus the wrapped filter core rod 12 is brought to the desired diameter. As a further alternative, instead of the melting bath 23 a further extrusion press can be provided (not shown in FIG. 3) that is used to apply a layer of hot melt adhesive around the filter core rod 12 in the manner of a cable insulation. Subsequently, as already shown in the exemplary embodiment of FIG. 1, a second wrapping material 21 is pulled off from a bobbin 20 and brought into the area of the filter core rod 12 wrapped with the first wrapping material in order to then wrap by means of a rod maker 15 the second wrapping material 21 around the filter core rod 12 provided with the first wrapping material 18. Subsequently, filter elements 24 or filter segments 24 are cut off from the rod.

[0031] List of Reference Numbers

[0032]10 Extrusion press

[0033]11 Extrudate

[0034]12 Filter core rod

[0035]14 Processing device

[0036]15 Rod maker

[0037]16 Filter

[0038]17 1^(st) bobbin

[0039]18 1^(st) wrapping material

[0040]20 2^(nd) bobbin

[0041]21 2^(nd) wrapping material

[0042]22 Filter core

[0043]23 Melting bath

[0044]24 Filter element

[0045]25 Longitudinal axial direction

[0046]26 Round nozzle 

1-15. (canceled)
 16. A method for producing filter segments for one of multi-segment filters and filters for tobacco products comprising: extruding a rod-shaped extrudate from a starting material; and wrapping the extrudate with at least one of a compressible and an elastic first material.
 17. The method according to claim 16, further comprising: heating the extrudate before the wrapping.
 18. The method according to claim 17, wherein the heating is carried out at a temperature range of 600° C. to 1000° C.
 19. The method according to claim 16, further comprising: heating the extrudate by microwaves.
 20. The method according to claim 16, wherein the first material is one of impermeable to smoke and substantially impermeable to smoke at least in a longitudinal axial direction.
 21. The method according to claim 16, wherein the wrapping with the first material is carried out by at least one of: a further extrusion process, dipping in a melting bath, wrapping with a strip of the first material, and by wrapping with the first material arranged on a soft carrier strip.
 22. The method according to claim 16, wherein the first material is a hot melt adhesive.
 23. The method according to claim 22, wherein the hot melt adhesive is an ethylene vinyl acetate copolymer.
 24. The method according to claim 16, wherein the first material is one of foamed and foamable.
 25. The method according to claim 16, wherein the first material is composed of a cellulose acetate tow of high density.
 26. The method according to claim 24, wherein the cellulose acetate tow is wrapped around the extrudate transverse to a rod direction of the extrudate.
 27. The method according to claim 24, wherein the cellulose acetate tow is spirally wrapped around the extrudate transverse to a rod direction of the extrudate.
 28. The method according to claim 16 further comprising: wrapping the extrudate wrapped with the first material with a second material.
 29. The method according to claim 28, wherein the extrudate is wrapped in a rod process with at least one of the first material and the second material.
 30. The method according to claim 16, further comprising: cutting the wrapped extrudate into segments of predeterminable lengths.
 31. At least one of a filter and filter segment for a multi-segment filter of a tobacco product produced according to the method claim 16 comprising: a core that is wrapped with at least one first wrapping material that is at least one of compressible and elastic, wherein the first wrapping material is one of substantially impermeable to smoke and completely impermeable to smoke.
 32. At least one of a filter and filter segment according to claim 31, wherein the core is composed of an extrudate.
 33. At least one of a filter and filter segment for a multi-segment filter of a tobacco product produced according to the method claim
 16. 34. A tobacco product having one of a filter and filter segment for a multi-segment filter, the one of a filter and filter segment comprising: an extruded core that is wrapped with at least one wrapping material that is at least one of compressible and elastic, wherein the first wrapping material is at least substantially impermeable to smoke.
 35. The method according to claim 34, wherein the at least one wrapping material is composed of a cellulose acetate tow. 